[Adverse effects of valproic acid in epileptic infants and adolescents]

Although valproic acid as well as its derivatives are effective in the treatment of some epileptic seizures, they are not free of adverse side effects. The purpose of this work was to describe the collateral clinical effects of valproic acid, the associated changes that take place in some serum laboratory parameters, and correlations among these adverse clinical effects, drug serum level and therapeutic response. One hundred patients aged 7 months to 19 years (average 5 year and 6 month old) were followed for at least 13 months. Clinical collateral effects were observed in 14% patients, anorexia and hair loss being the most frequent. One third of patients showed raised serum alkaline phosphatase and transaminases values, while lower than normal prothrombin time and platelet counts were detected in 4% and 1% of patients, respectively. In one patient treatment was interrupted because of low platelet counts which persisted in spite of drug withdrawal, but basal counts were not done, so it is not possible to establish causal relationships between both events. No correlation between adverse clinical symptoms and valproic acid plasma levels was observed. In spite of the fact that basal laboratory values were not known and that abnormal tests were not repeated for confirmation, collateral clinical effects and laboratory findings associated to treatment with valproic acid seemed not severe in this series. Anyway, taking into account drug characteristics, it should always be used with caution.